A high strength, anti-corrosion and sustainable separator for aqueous zinc-based battery by natural bamboo cellulose

Although aqueous zinc-based batteries (AZBs) have aroused extensive research, there are little studies to develop a separator specifically for AZBs, and the widely used Glass Fiber (GF) has poor mechanical strength, which is difficult to meet the requirements of AZBs. Here, a bamboo cellulose membrane (BCM) with natural nano-scale pores is developed by cellulose nanosheets self-assembled, which can be used as a special separator for AZBs. The hierarchical structure formed by cellulose nanosheets endows BCM with a tensile strength up to 81 MPa, 150 times that of GF, able to well block the penetration of zinc dendrites. The rich natural nano-scale pores in BCM can help to facilitate the homogeneous Zn2+ flux at the surface of zinc anode to achieve uniform deposition. Moreover, BCM shows excellent anti-corrosion properties in a wide pH (3.6–13.6) range. The zinc symmetric cell equipped with BCM exhibits much prolonged cycle life, e.g. up to 5000 h and 5000 h (0.5 mA cm−2 0.5 h) in 3 M Zn(CF3SO3)2 electrolyte and 1 M KOH electrolyte, in contrast to 30 h and 4 h for the cell with conventional GF separator. This work demonstrates that developing special separator is very important for the construction of high-performance AZBs.